Power actuated typing mechanism for business machines



Aug. 7, 1956 w. H. WADE 2,757,773 POWER ACTUATED TYPINGY MECHANISM FOR BUSINESS MACHINES Filed May 28, 1954 4 Sheets-Sheet l FIG.I

WILLARD H.WADE

INVENTOR' ATTORNEY Aug. 7, 1956- w. H. WADE 2,757,773

POWER ACTUATED TYPING MECHANISM FOR BUSINESS MACHINES Filed May 28, 1954 4 Sheets-Sheet 2 II/IIIIIIIIAI III WILLARD H. WADE INVENTOR VZZJM ATTORNEY 7, 1956 w. H. WADE 2,757,773

POWER ACTUATED TYPING MECHANISM FOR BUSINESS MACHINES Filed May 28, 1954 4 Sheets-Sheet 3 ARD H. WADE NVENTO ATTORNEY o (0 IO Aug. 7, 1956 w. H. WADE POWER ACTUATED TYPING MECHANISM FOR BUSINESS MACHINES 4 Sheets-Sheet 4 Filed May 28, 1954 WILLARD HzWADE INVENTOR ATTORNEY United States Patent n Corona Inc., Syracuse, N. Y., a corporation of New York Application May 28, 1954, Serial No. 433,680

15 Claims. c1. 197-17 The invention relates to improvements in power actu} ate'd typing mechanism for business machines and, more particularly, to typing mechanisms of the kind wherein each type bar action of a system of such actions has an appended driving earn, the driving cams being individually and transitorily engageable with a power roller to impart power driven printing impulses to the actions to which they are appended. l

General purposes of the invention are to pro'vide an improved construction and arrangement of such a' type bar action, its driving cam and means for en aging the cam with the power roller, and to provide an improved arrangement of each such type bar action and of a set of such actions with respect to the power roller whereby noise, shock and wear in operation are reduced, costs of manufacture and assembly are reduced, slippage, between the cams and power roller is avoided, uniformity of load 2,757,773 l atented Aug. 7, 195g g Figure 7 is a top plan view of one of the set of identical driving canis for the type bar actions; I Figures 8 and 9 are rear and side elevations respectively of an adjustable cam substitutive for the cams of Figures 1 to 7; and

Figure 10 is a sectional view on the line 1010 of Figure 9.

The improved typing mechanism is shown embodied in akind of typewriter having a roller platen 10 journalled in a carriage, not shown, which is mounted to travel transversely of the main frame of the typewriter. The main frame has upstanding side plates 11 rotatively supporting a rubber faced power roller 12 which extends horiion'tally between said plates and is constantly rotated in the direction of the arrow in Figure 2 by a suitable motor while the machine is in use.

A re'arwardly inclined and radially slotted type bar segment 13 and its attached type bar rest 14 are carried by a case shiftable support 15 between the side plates 11. T hi suppon is shiftable downwardly and forwardly, by known case shifting means, not shown, from a normal position for lower case typing to a shifted position for upper case typing. The segment and rest supportthe usual set of normally cumbent and arcuately arrayed front strike type bars 16 which are pivoted in the segment slots on the usual arcuate pivot wire 17 carried by the segment, the two medial type bars of the setbeingpivotjed imposed on the power roller in driving the respective cams is attained, like driving operation of all the cams by the power roller is attained, and uniform density of type impressions is attained.

Further purposes of the invention are to ,provideimproved and uniformly operable means for effective selec: tive engagements of the cams with the power roller and for variable regulation of the dip of the controlling keys for the type bar actions.

,Another purpose of the invention is to provide anset of such type bar actions wherein most of the corresponding parts of the respective actions are identical. t

A specific purpose of the invention is to improve typing mechanism of the general kind disclosedin the prior applications for patent of Charles H. Kennedy, Jr., and Willard H. Wade, filed October 23, 1952, Serial, No. 316,486 and of Willard H. Wade, Serial No. 358,766, filed June 1, 1953. v v n Other purposes and advantages of the invention will be apparent from the following descriptionof the invention with reference to the accompanying drawings.-

In the drawings: p

Figure 1 is a fragmentary top plan view ofa known style of front strike typewriter equipped with power actuated typing mechanism embodying the invention. in a preferred form, certain parts of the typewriterbeing entirely omitted and others broken away for clarity of illustration of certain features of the invention;

Figure 2 is a fragmentary vertical sectional view taken medially of the set of type bar actions of the typewriter on the line 2-2 of Figure 1; H V

Figure 3 is a detail front elevation of one of the key stems and its supporting means;

Figure 4 is adetail sectional View on an enlarged scale taken on the sameline as Figure 2;

Figure 5 is a detail sectional view on the line"5" ---5 of Figured isa diagrammatic view on an enlarged sc'ale showing certain stages of operation of both a medial and an end type' bar action;

equal distances laterally from the lowestpart of the pivot wire. The type bars all swingas usualito a common printing point through printing strokes of the same amplitude. Only a medial and an end type bar of the set are shown.

The improved means for eifectiugselective actuation of the type bars by the power roller now will be described. Each type bar has an individual operating train. Each train comprises an upstanding lever 18, a link 19' connect'ed to the upper end of said lever by a pivot 20 and connected by a pivot 21 to the lower end of a short operating arm l6 of the type bar which normally extends downwardly and rearwardly from the type bar pivot wire. Individual returning springs 22 are connected to the levers and to a spring anchor bar 23 to bias each type bar and its operating train to a normal position of rest.

The levers 13 are levers of the first class which ,normally stand in a straight row across the typewriter behind the power roller and are fulcrumed on acornmon straight fulcrum rod 24 which extends horizontally across the typewriter between the side plates 11 and is carried by .a bar 25 which extends under the type bars behind the power roller and is fixed to saidplates. ,The levers are guided in vertical slots 26 in the forward portion of bar 25, said bar portion preferably having an upper edge which curves upwardly from the middle toward the ends of the bar to provide guide slots of increasing height from the medial to the end levers. The links 19 are of equal length and normally are in parallelism. The pivots 20 are normally located in an are which lies in a plane P parallel to the plane containing the pivot Wire 17, and the pivots 21 are normally located in an are which lies in a plane parallel to plane P, said two arcs and the arc of the pivot wire having a common axis normal to said planes. The upper arms of the two medial levers are of equal length the upper arms of the other levers are graded upwardly in length progressively from the medial to the end levers, and the upper ends of said arms are bent inward to afford parallelism of the links. v

The springs 22 are of equal length and strength and normally are perpendicular to plane P. The springs are connected to the upper arms of the levers at uniforinratio points, and their anchor bar 23 is located behind the levers and is fiiied to the top" face of the bar 25 which carries the lever fulcrum rod 24. The springs thus act with the same effective returning force on the several levers.

Extending fore and aft of the typewriter below the power roller, the set of levers 18 and the bar 25 is a set or row of parallel and identical key operable levers 27. Levers 27 are formed of sheet metal and are fulcrumed at their rear ends on a straight horizontal fulcrum rod 28 carried by a fulcrum bar 29 which is fixed to side plates 11 and is provided with vertical guide slots 30 for said levers. Adjacent their forward ends the levers 27 are guided in vertical slots 31 in a key lever guide comb 32 which is held to side plates 11. To this comb and to the respective levers 27 are anchored individual returning springs 33 for the levers.

Downward rocking of the levers 27 is limited by a straight horizontal stop rod 34 carried by the comb 32. The levers are selectively depressible by key-carrying sheet metal plungers or stems 35 which are located forwardly of comb 32. Each plunger has a key 36 fixed on its upper end, said keys being arranged in four stepped banks or rows and being inclined forwardly and downwardly.

The plungers are guided to move in a downwardly and rearwardly inclined path when depressed and are arranged for equal dip to rock the levers downwardly through equal angles into contact with stop rod 34. Each plunger has a closed guide slot 37 intermediate its ends and a guide slot 38 at its lower end, the lower end of slot 38 being open and its upper end closed. Normally the plunger slots 38 are aligned across the typewriter with the shanks of headed and normally axially aligned horizontal studs 39 engaged in and at the upper ends of said slots and fixed to the levers 27. Slots 37 and 38 are parallel and downwardly and rearwardly inclined.

A plunger guide comb 40 is fixed to the side plates 11 and has straight horizontal guide rods 41 and 42 clamped respectively in its front and rear edge portions. Said edge portions have respectively guide slots 43 for the plungers of the two forward banks of keys and guide slots 44 for the plungers of the two rear banks of keys, the rod 41 passing through plunger slots 37 of the two forward key bank plungers and the rod 42 passing through plunger slots 37 of the two rear key bank plungers. Upward movements of the levers and plungers are limited by the engagement of stop fingers 45 on the plungers with a stop pad 46 secured to the bottom of guide comb 40, which fingers are permanently bendable up and down for adjustment.

Each key operable lever 27 has pivoted thereto by a horizontal transversely extending pivot 47 one of a straight transverse row of identical sheet metal and normally upstanding dogs 48 whose pivots normally are located preferably directly under the fulcrum rod 24 for the type bar actuating levers 18. Each dog has at its upper end a laterally extending lug or nose 49 spaced above and overhanging the upper edge of the key operable lever to which the dog is pivoted, the rear edges of said lugs 49 preferably normally lying in the vertical plane containing the axes of rod 24 and the dog pivots 47. Springs 50 are connected to the respective key operable levers 27 and dogs 48 to normally hold the dogs upright with their rear edges engaged with laterally extending stop pins 51 on the respective levers 27. Preferably the dog pivots are carried by rearwardly extending fingers 27' formed on the sheet metal levers 27, which fingers are permanently bendable up and down for adjustment of the dogs.

The dogs are movable individually downward by depression of the respective keys to individually rock clockwise the respective ones of a straight transverse row of cam tripping or rocking levers 52 which normally are in register across the typewriter. The lower arms of the type bar actuating levers 18 have terminal end portions which normally are in register across the typewriter above the row of key operable levers 27 and behind the upper ends of the row of dogs. The cam tripping levers are pivoted to the lower end portions of levers 18 equidistant from the fulcrum rod 24 of levers 18 by normally axially aligned pivots 53 to rock about axes parallel to said fulcrum rod. Each lever 52 has a short normally forwardly and horizontally extending arm which normally is overhung by the nose 49 of an adjacent dog 48. Each lever 52 also has a longer arm and the outer end portions of these arms normally are located between the power roller 12 and the lower arms of the row of type bar actuating levers 18. Each such longer arm of the levers 52 carries a horizontal cam tripping or rocking pin 54 disposed parallel to the rod 24 and lever pivots '53. The pins 54 are each engaged in a slot 55 in a different one of a row or set of identical driving cams for the type bar actuating levers 18.

Two novel and alternatively usable forms of driving cams are shown, one having an eccentric tread portion the eccentricity of which cannot be adjusted, and the other having an eccentric tread portion and means for adjusting the eccentricity of said tread portion. The latter form of cam is shown in Figures 8 to l() and will be described following a description of the typewriter as illustrated in Figures 1 to 7 and as equipped with earns 56 of identical size and shape.

The cams 56 are rigid sheet metal cams formed in one piece. Each cam is appended at one of its ends to the lower arm of a different one of the type bar actuating levers 18 by a pivot 57 disposed parallel to the fulcrum rod 24 of said levers. The cams normally extend forwardly and upwardly between the power roller 12 and the row of levers 18 to free ends of the cams at which each cam is formed with a laterally extending stop lug 58. The upper arm of each lever 18 is formed with a forwardly extending stop lug 59. Identical cam returning springs are connected to spring anchorages 61 and 62 on the cams and the stop lugs 59, respectively, and normally hold the cams rocked upwardly counterclockwise and with the stop lugs 58 and 59 in engagement. Stop lugs 58 are permanently bendable toward and from the stop lugs 59 for adjustment.

Each cam is formed at its foremost edge with a lat erally projecting tread portion 56' which is eccentric to the cam pivot and is of short length and adapted to be brought in rollable engagement with the power roller by a slight downward rocking movement of the cam about the cam pivot as more fully hereinafter described. Each cam tread portion 56' terminates short of the ends of the cam and progressively recedes from the cam pivot from one end of the tread portion to the end thereof 'which is nearest the free end of the cam.

Certain of the parts heretofore described have novel arrangements now to be described which are important features of the invention. In the normal rest condition of the typing mechanism these parts have the following described arrangement.

The cam pivots 57 normally are positioned on a curved locus A which is concentric with the axis of the power roller, said pivots being carried by the lower arms of the levers 18 at uniform ratio points on said levers, and the pivots of the two medial cams being coaxial and closest to the lever fulcrum rod and preferably directly thereunder. From the two medial cams to the two end earns the cam pivots are located progressively farther downward on said locus, the pivots of the two ends cams being coaxial and farthest from the fulcrum rod 24.

The spring anchorages 62 normally are located at uniform ratio points on the graded upper arms of levers 18 and normally are positioned on a curved locus B. The pairs of engaged stops 5859 normally are engaged at uniform ratio points on the levers 18, which points normally are positioned on a curved locus C. Spring anchorages 61 are located at equal ratio points on the set of identical cams and normally are positioned on a curved locus D. Loci B, C and D also are concentric with the power roller axis.

The earn rockingpins'4 on the cam tripping levers SZ normally are positioned on a curved locus E which is concentric with the power roller axis, The identical cam slots 55 in which pins 54 are engaged are radial to the cam pivots and are so identically located in, the cams that the lower edge of each cam slot nojrma'lly extends along a straight line connecting the axes of the cam pivot and the power roller. Pins 54 are mounted on levers 52 at distances from the normally axially aligned pivots 53 of said levers which are identical for the pins on the two medial levers and so progressively decrease to the pins on the two end levers that said pins normally are engaged in slots 55 at equal ratio points on the cams or equidistant from the cam pivots and adjacent. the rear ends of slots 55. The described normal, arrangement of the cams necessarily normallylo'cates the forward ends of the slots 55 on one curved locus and the rear ends of the slots on another curved locus both of which loci are concentric with the power roller axis. A x

The tread portion 56 of each of the identical cams normally is located entirely above the radial line through the cam pivots on which lies the lower; edge of the cam slot 55 Each such cam tread portion 56 normally is so spaccdin its entirety above a straight line connecting the axes of the cam pivot and the power roller that,,as. indicated' in Figure 6 in full lines, downward rocking of the cam about its pivot from normal position will bring'the lower end of the cam pivot into drivable engagement with the power roller periphery at said straight line connecting said axes. The foregoing ,normal arrangement of the identical cams necessarily locates the upper or trailing ends of their tread portions on one curved locus and thelower or leading ends of their tread portions on another curved locus with the latter ,tends of thettread portions-closest to theperiphery of the powerroller, both of which loci also are concentricwith thepower roller axis. It also normally disposes the cams in a row across the t y pewriter behind and along the power roller with said'cams and their tread portions staggered progressively downward around the power roller from the two medial camsto the two end cams in two helicalpaths which wind front the middle toward the ends of the roller. v

x The radii of loci A to E decreaseprogressivcly from that of locus A to that of locus The noifmalclear ance between the lower ends of the tread portions of the cams and the power roller preferably is quite small, as shown, and said lower tread portion end s'are the closest parts" of the cams to the power roller. While th'estopsand 59 are engaged the levers may rock throughout full strokes of th e type bars Without contacting the cams with the power roller. I i v In the construction shown and above described it will be obvious that, on full printing strokes of the type the chord'al amplitudes of the arcs through which the pivots 20 of the'type bar actuating links 19 are'moved forwardly are identical, the chordal amplitudes of thearcs through whic h the cam pivots 53'a r e movcdrearward also are identical, and the angular movements of levers 18 decrease progressively from those of the two medial levers to those of the two end levers.

The eccentric tread portion 56 of each carn preferably is curved longitudinally in a circular path on a radius R (Figure 6) whichis quite long compared with the size of the cam, said radius extending through the cam pivot axis to the end of least eccentricity of the tread portion. In the preferred embodiment of the invention shown in Figures 1 to 7 no provision is made for forcible disengage ment of the cams from the power roller. Each am is rockable from rest position clockwise about its pivot through a like angle to drivably engage its tread portion with the power roller at the lower end of said portion with the radius R of said portion radial to the axis of the power roller, as is indicated in Figure 6 in solid lines with respect to" one of the two medial cams and oneo f the two end cams. The treadportion thereafter will roll for its full length on the periphery of. the ppw'er roller until the upper end of said tread portion arrives at a line which is radial to the power roller axis and passes through the pivotal axis of the cam, as indicated also in Figure 6 in dot and dash lines, whereupon the acquired momentum of thetype bar action actuated by the cam will carry the cam bodily in translation out of engagement with the power roller. 7 a H a The aforesaid full rolling engagements of the tread portions of the cams with the power roller cause like angles of clockwise rocking movements of the cams about their pivots and concomitantly cause like movements of translation of the cams which drive the cam pivots 57 through arcs of like chordal amplitude; as indicated in Figure 6, which so variably rock the respective levers 18 that the link pivots 20 at the upper ends of said levers move through arcs of like amplitude to swing the type bars from their rest positions through like angles toward the platen 10 at like rates of speed. The type bars are driven at a constantly accelerating rate, equal extents of rolling movement of the cams on the power roller driving the cam pivots through progressively increasing steps, as indicated by short lines S in Figure 6, for rocking of the respective levers 18 at identical accelerating rates.

The length and eccentricity of the tread portion of each or the identical cams are such that the cams disengage from the roller as link pivots 2i) arrive at a plane P parallel to plane P, and also as the type bars complete like partial printing strokes. The extent of such partial printing strokes of the type bars is indicated at Figure 2. Thereafter the momentum of any actuated typebar action carries its type bar to its printing position indicated at 16 and carries link pivot 20 of said action to a plane P Figure 2, which is parallel to planes P and P. v 7 L y The amount of stretch imparted to each of the identical cam'fret'urning springs 66 by the movement of its associated cam into engagement with the power roller and by subsequent rolling of the cam until it disengages from theiroller' is the same for all of said springs and cams. immediately upon disengagement of any cam from the rollerthe cam is restored to itsrest relation to its carrying lever 13 and will clear the roller on the return stroke of the type bar action. The springs 60 act with the same efficiency on the respective cams. After any cam carrying type; bar action completes a printing action it is immediately restored to rest position by its returning spring 22. These identical springs are stretched the same amount by the full printing strokes of the respective type bar actions and act thereon with the same efficiency. It the control: ling key for any of the type 'bar actions is held depressed until the power driven action returns to, or nearly to, its rest position, the forward end edge of the short arm of the tripping lever 52 for the cam appended to the type. bar action will strike the rear edge of the nose 49 of the actuating dog 48 for said cam and rock the dog forward until the type bar action and its appended cam are fully returned to normal rest position. Upon restoration of said key to normal position, the dog will rise and be restored to normal position by its restoring spring 50. Springs 50 are Weaker than springs 60, and each power driven type bar action can print but once for each depression of its controlling key.

The improved system of power driven type bar actions theoretically is effective to cause all of the type bar actions to impact the types against the platen with the same force. However, as is well known, the force of type impact must be variably regulated from action to action if type imprints of uniform density are to be attained. Such regulation may be attained with the foregoing system of type actions in various known ways.

One such way is to provide individually adjustable knock-out devices for the respective cams against which the cams are driven by the power roller at variable points in"the rolli'ng engagements of the cams with the roller to forcibly disengage the cams from the roller. Such means cause noise and shock and also cause objectionable wear of the cams and of the rubber-faced power roller.

Another such known way to individually regulate the type impacts is shown in Figures 2 and 4 wherein individually adjustable buffering means for the several type bar actions are shown which act on the type bar actions during their printing strokes only after the cams disengage from the power roller. This buffer means shown is constructed like that disclosed in the previously mentioned Wade application for patent. It comprises individual buffer plungers 63 slidably guided to move fore and aft of the typewriter in a support 64 extending across the typewriter above the power roller and secured to the main frame side plates 11. Each plunger has its rear end opposed to the upper arm of a different one of the levers 18, said plungers being individually urged to normally rearwardly projected limits by individual springs 65 which resist forward movements of the plungers by said lever arms with forces variably regulative by screws 66 which are variably screwable into the support against the forward ends of the springs. Since the levers 18 move through progressively diminishing angles from the medial to the end levers, the rear ends of the plungers normally are so stepped progressively rearward from the medial to the end plungers that, as indicated in Figure 2 wherein a medial and an end plunger are shown, initial engagement of the levers and plungers will occur at like points in the printing strokes of the type bars, and that, as indicated in Figure 4 by the two showings in dot and dash lines of the positions of one of the medial levers at the times of cam disengagement and of type impact, the levers can act to drive the plungers forwardly only during the momentum portions of the printing strokes of the type bars.

A third way to attain variable regulation of the type impacts is disclosed in the previously mentioned Kennedy and Wade application for patent by providing the cams with means whereby the eccentricity of the tread portions of the cams may be variably adjusted. Figures 8, 9 and 10 show one of a set of identical adjustable cams of improved form which may be substituted in the above described typewriter for the cams 56 to attain such individual regulation of the type impacts without employing the above described buffering means,

These adjustable cams are mounted in the machine on the cam pivots 57 like the earns 56 and in the same arrangement and are connected with the tripping levers in the same way, said cams having cam slots 55, return spring anchor holes 61, and tread portions 56 similar to those of cams 56. Each adjustable cam has a sheet metal body portion 67 for mounting on one of the cam pivots 57 and in which the slot 55 and the spring anchor hole 61 are formed. Instead of the stop lug 58 of cam 56, the body portion of each adjustable cam is formed with a stop lug 68 for normal engagement with the stop lug 59 of the lever 18 to which the cam is pivoted. The tread portion 56 of each adjustable cam is formed on a pivotally adjustable sheet metal portion 69 of the cam and is of the same length and longitudinal curvature as the tread portions of cams 56. Cam portions 67 and 69 are pivotally connected closely behind the lower end of tread portion 56- by a pivot 70 which is parallel to the cam pivot 57. An eccentric 71, having a slotted head 72 for rotation by a screw driver, is held to cam portion 67 by a journal part 73 of the eccentric which is rotative in cam portion 67 and is parallel to pivot 70 of cam portion 69. Eccentric 71 is engaged in a slot 74 in pivoted cam portion 69. By rotatively adjusting the eccentric the pivoted portion 69 of the cam may be variably adjusted around its pivot 70 to adjust the eccentricity of the tread portion of the cam. A lock washer 75 serves to hold the eccentric in adjusted position and prevent accidental movement of cam portion 69 about its pivot 70.

Collective or universal regulation of the type impact forces for all of the type bars may be attained in a known 8 manner by varying the rate of revolution of the power roller.

The improved typewriter may be provided with a straight universal bar 76 fixed to a rock shaft 77 journalled in the main frame side plates 11. This universal bar is rockable through like angles by the respective levers 18 to actuate a ribbon mechanism (not shown) by means of projections 78 on the lower arms of the levers 18, which projections are arranged to engage the universal bar at points which, from the medial levers to the end levers, progressively approach the rock shaft 77.

Each type bar action preferably is provided with improved overthrow limiting stop means for its appended driving cam, each such means comprising a laterally extending stop stud 79 fixed to the lower arm of the lever 18 of the type bar action and normally engaged in the forward end of a slot 80 formed in the cam tripping lever 52 for the cam. In normal typing operations the pins 79 never engage the rear ends of slots 80 but, if two or more type bars become jammed while their driving cams are engaged with the power roller, continued rocking of said cams about their pivots by the power roller through slightly more than the normal angle of such rocking will cause pins 79 to engage the rear ends of slots 80 and arrest rocking of the cams and prevent both injurious stretching of the cam returning springs 60 and dragging of the upper ends of the cams underneath the power roller.

Some typists prefer power typewriters operable with a very short key dip and others prefer a longer key dip. A feature of the present invention resides in the provision of novel means to regulate the key dip without changing the inclination of the key tops. It will be noted that in Figure 2 of the drawings the noses 49 of the dogs 48 normally are spaced above the upper edges of the short forwardly extending arms of the cam tripping levers 52. This normal spacing may be increased or diminished by bend-ably adjusting the stop lugs 45 on the key carrying plungers 35 respectively downwardly and upwardly, thereby respectively increasing and diminishing the key dip but leaving the degree of key inclination unchanged.

Preferably the power roller engaging faces of the tread portions of the cams are roughened as indicated and as is common in the art.

I claim:

1. Power actuated typing mechanism for business machines comprising pivoted front strike type bars normally cumbent in an arcuate array in which the type bars are disposed progressively higher from the medial to the end ones of the array, an array of upstanding levers individually rockable about a common straight fulcrum axis which is disposed horizontally and transversely of the array of type bars, individual operating links connecting the type bars and levers seriatim along the type bar and lever arrays at points on the type bars equidistant from the type bar pivots and at points on the levers which are progressively higher from the medial to the end levers of the lever array, means biasing each lever to a rest position from which it is rockable to impart a printing stroke to the type bar linked thereto, a cylindrical power roller opposed to the array of levers with its axis parallel to the fulcrum axis of the levers, an array of roll-free cams each rotatively journalled on a different one of the levers with its axis parallel to the power roller and so positioned on the lever that the ratio of the distances between the lever axis and the axes of the cams to the distances between the lever axis and the points of connection of the links with the levers is identical for all of the levers, the rest positions of the cams and the positions of the cam axes on the array of levers being such that, in the rest positions of the cams and levers, all of the cams are rotative through a like angle into roll-free engagements with the power roller which rock the levers from rest position, and means for individually rotating the cams into engagement with the power roller.

2. Power actuated typing mechanism for business machines, as claimed 'in claim 1, in which the cams are of identical size and shape and their rest positions on the array of levers are such that they are rotative through like total angles by the power roller which so rocks the levers that each lever swings its connected type bar through the same angle part way through a printing stroke in consequence of said total angle of rotation by the power roller of the cam journalled on the lever.

3. Power actuated typing mechanism for business machines, as claimed in claim 1, having means for adjustably and individually buffering rocking movements of each of the levers from its rest position after the cam journalled on such lever rolls free of the power roller, and also having cams-which roll free of the power roller before rocking the levers on which they are journalled far enough to swing their connected type bars through a full printing stroke to thereby permit the type bars to complete their printing strokes by momentum.

4. Power actuated typing mechanism for business machines, as claimed in claim 1, having on said array of levers cams of identical size andconstruction, each of which cams has a tread portion for roll-free engagement with the power roller and also has means to adjust its tread porti'on' eccentrically to the cam axis.

Power actuated typing mechanism for business machines comprising a row of upstanding levers which are rockable individually about a common and straight horizontally disposed fulcrum axis and are biased individually to a rest position, a cylindrical power roller opposed to the row of levers with its axis parallel to the fulcrum axis of the levers, a row of cams each journalled on a different one of the levers for rotation about an axis which is parallel to those of the levers and power roller and is so located on the lever that, when all of the levers are in rest position the axes of the row of cams are equidistant from the axis of the power roller and are stepped progressively therearound in the same direction from the medial to the end cams of the row of cams, individual means rotatively biasing each cam to a power roller clearing rest position on the lever on which the cam is journalled, individual means to rotate each cam from its rest position into a roll-free engagement with the power roller for a further rotation of the cam by said roller which rocks from rest position the lever on which the cam is journalled, each cam having a power roller engaging tread of the same length which is increasingly eccentric from one to the other of its ends to the cam axis and which is initially engageable at said one of its ends with the power roller, said ends of the cam treads intially engageable with the power roller being, when all of the cams and levers are in rest position, all equidistant from the power roller and each being the same distance above a straight line connecting its axis and the power roller axis, and a set of type bars each connected with a different one of the levers to be driven by a rollfree engagement with the power roller of the cam on the lever through a printing stroke which is completed by momentum after the cam rolls free of the power roller.

6. Power actuated typing mechanism for business machines, as claimed in claim 5, wherein the individual means for rotating each cam into initial engagement with the power roller comprises cam rotating levers each fulcrumed on a different one of the upstanding levers and each having a pin and slot connection with the cam journalled on the upstanding lever upon which the cam rotating lever is fulcrumed, the slot of said connection between each cam and its rotating lever being so disposed as to extend in the rest position of the cam and upstanding lever substantially along a straight line connecting the axes of the power roller and cam, and key operable means individual to each cam rotating lever and operable thereupon to rock the same to eifect initial cam engagement with the power roller.

7. Power actuated typing mechanism for business ma- .10 chines,- as claimed inclaim 6; wherein the pins of the pin and slot connections of the cam rotating levers with the cams are engaged with theslots of saidv connections equidistant from the power roller axis in the rest positions of the cams and the upstanding levers.

8. Power actuating typing mechanism for business machines comprising a power roller, a type bar actuating lever opposed to the power roller and rockable about an axis which is parallel to the power roller, means biasing said type bar actuating lever to a rest position, a roll-free cam rotativc on the lever about an axis which is parallel to the power roller, means rotatively biasing: the cam in one direction into a power roller clearing rest relation to the type bar actuating lever, a cam rotating lever rockable on the type bar actuating lever about an axis which is parallel to the cam axis, said cam rotating lever and cam having apin and slotconnection the slot of which connection extends longitudinally substantially between the cam and power roller axes when the camand type bar actuating lever are both in their rest positions, an up and down rockable key operable lever, 21 dog pivoted on the key operable lever andhaving a nose normallyoverhanging a part of the cam rotating lever to rock the latter to rotate the cam in the opposite direction from its rest position into engagement with the power roller when the key operable lever is downwardly rocked from a rest position to which it is biased to return, and a spring connecting the dog and key operable lever to normally position the dog on the lever with its nose overhanging the cam rotating lever and to permit said dog to yield for return of the cam and its rotating lever and the type bar actuating lever to their respective rest positions while the key operable lever is held downward- 1y rocked.

9. Power actuated typing mechanism for buisiness ma chines, as claimed in claim 8, wherein the cam comprises a body portion rotative on the type bar actuating lever about said cam axis, a tread portion pivoted on the body portion for pivoted adjustment relatively to the body portion about an axis parallel to that of the cam, and a rotatively adjustable eccentric journalled on one of said cam portions and engaged in a slot in the other cam portion for pivotally adjusting the tread portion of the cam relatively to the body portion of the cam, said eccentric being rotatively adjustable about an axis parallel to the pivotal axis of said cam tread portion.

10. Power actuated typing mechanism for business machines comprising a row of upstanding levers of the first class rockable individually about a common straight horizontal fulcrum axis and each biased to a position of rest, a cylindrical power roller opposed to the row of levers with its axis parallel to the fulcrum axis of the levers, a row of identical cams each journalled on a different lever below the lever fulcrum axis for rotation about an axis parallel to those of the levers and power roller, means rotatively biasing each cam in one direction to a power roller clearing rest relation to the lever on which the cam is journalled, each cam having a power roller engageable tread which is progressively eccentric to the cam axis from one to the other end of the tread, said axes and said one ends of the treads of the row of cams being, when all the levers and cams are in the rest position, stepped progressively downward around the power roller axis from the medial to the end cams of the row of cams with the cam axes all equidistant from the power roller axis and with said one ends of the treads of the cams all equidistant from the power roller axis and each such tread end of each cam disposed the same distance above a straight line connecting the power roller axis with the axis of the cam, means for rotating the cams individually against their bias into engagement with the power roller, and a set of type bars each operatively connected with a difierent one of the levers at a point above the lever fulcrum axis the distance of which from said axis progressively increases from the medial to the end levers of the row of levers.

11. In a machine of the class described, power actuated typing mechanism comprising an array of levers rockable individually about a common straight fulcrum axis and each biased to a rest position, an array of type bars each connected with a different one of the levers for impulsion through a printing stroke through rocking of the lever from rest position, a cylindrical power roller opposed to the array of levers with its axis parallel to the fulcrum axis of the levers, an array of roll-free cams each engageable with the power roller for rotation thereby and each journalled on a different one of said levers for rotation by the roller about an axis which is parallel to that of the roller to rock from rest position the lever upon which it is journalled, means rotatively biasing each cam to a power roller clearing rest position on the lever on which it is journalled, said cam axes being variantly located among the levers at different distances from the lever axis and the rest positions of the cams and levers being such that each cam, at least substantially throughout its rotation by the power roller, contacts the roller directly between the axis of the roller and the cam axis as the lever on which the cam is journalled rocks from rest position, and inidividual means 2 for rotating each cam from its rest position on the lever on which it is journalled into engagement with the power roller.

12. A machine, as claimed in claim 11, wherein the cams are identical earns.

13. A machine, as claimed in claim 11, wherein the came are of identical size and construction, and wherein each cam has a tread portion for roll-free engagement with the power roller and also has means to adjust its tread portion eccentn'eally to the cam axis.

14. A machine, as claimed in claim 11, wherein the cams are of identical size and shape, the axes of the cams are equidistant from the power roller axis when all of the levers are in rest position, and each cam has a tread portion for engagement with the power roller which is increasingly eccentric to the cam axis from one to the other end of the tread portion, which one ends of the References Cited in the file of this patent UNITED STATES PATENTS Kittel June 28, 1949 Petz Oct. 31, 1950 

